Temperature-indicating apparatus for vehicle-propelling motors



April 24, 1928.

l H. H. BoYcE TEMPERATURE INDICATINGAPPARATUS FOR VEHICLE PROPELLINGMO-TORS Filled July 29. 1925 Patented Apr. 24, 1928. l

UNITED STATES PATENT oFFlcE.

HARRISON H. BOYCE, OF JERIQHO, NEW YORK.

Applicatia mea July 2a, 1925. serial No. 46,731.

. In my Patent No. 1,206,781?, dated November 28th, 1916, I have,disclosed an invention in means for indicating the thermal condition ofinternal combustion engines of automobiles,l aeroplanes. and the like, vby which it is possible to secure at all times an indication of thethermal condition of the engine, said indication being rendered readableat the desired location as by means of l an indicating instrumentlocated on the vehicle dash board, which is connected by suitableoperative means with a temperature responsive element thermallyassociated with the engine or cooling system.

In the construction illustrated in said patent, the instrumentalityemployed comprises a temperature responsive element which isshown asimmersed in the cooling liquid in the return pipe of the engine, thistemperature responsive element being connected by a flexible tube to anindicating strument mounted on the vehicle dash. The

present invention relates to a system of the general character set forthin said atent and comprises particularly anim rov or alternative mode ofapplying te temperature responsive element'to the engine.

The specific construction illustrated in my patent embodying theimmersion of the d bulb'or temperature responsive element in thecooling` liquid, while'very eifective in securing the thermalresponsiveness `of the instrument, is vopen to certain objectionsfrom'a' mechanical standpoint in that it req'uires the making of anaperture in some part of the wall of the cooling system to admit thebulb and it also requires the conv structionr and maintenanceof a iiuidtight joint so as to prevent leakage. While a 1,40 satisfactoryconstruction of this character is vperfectly feasible with the exerciseof proper care there nevertheless exists the danger that when anattachmentof thel bulb 1s attempted by unskilled Ahands or in acareless.

In accordance withthe temperature of an outer surface of a motor wall,as for example the cooling jacket of an air cooled motor or the cylinderwall of a'motor of the air cooled type, may

for practical purposes be taken asv a sufficiently accurate measure ofthe temperature of the engine cylinder.

In the present a plication I propose to describe and claim t e inventionwith particular reference to air cooled motors. Inaddition, however, itis my intention to cover herein other features of my invention which areapplicable to a water cooled as well as an air 'cooled type of motor.

In the accompanying drawingsLin which I have illustrated certainpreferred embodiments of my invention:

Figure 1 is a side elevation, diagrammatic in'character, of an engine ofthe air cooled type, hood and a portion of the dash of an automobile.

Figure 2 is a detailed view in side elevation of thev means for securingthe temperature responsive element to the cylinder jacket.

Figure 3 is' an enlarged vertical sectional 'view through a portion ofthe engine cylinder and a temperature responsive elementattachedgthereto.

Figure 4 is a vertical sectional View of a form of indicating instrumentwhich may be employed in carrying out my invention.

Figure 5 is a' face view of the instrument, parts being broken away toshow the interior construction.

Figlure 6 is a diagrammatic view illustratmg t e application of onefeature of the invention to a water cooled motor.

Referring to the drawings in detail, and particularly to Figures 1 to 5,the numeral 1 designates an automobile engine provided with lcylinders.2 containing the customary l pistons 2. As shown, the side walls of thecylinders are'surrounded by cooling fins 3. As the i nitionandcombustion or explosion of the c arge takes place primarily in the upperends of the cylinders when the istonsd are at or near the upper limits otheir strokes, it will be seen that these portions of the cylindersconstitute combustion chambers (designated by the numeral 4) Where thegreatest temperature is reached.

The engine ,described is shown connected with the usual instrument board16 which forms a part of the vehicle body and which is as customarylocated immediately'in front being enclosed on the outer side b of thedrivers seat so that instruments placed thereon may be readily observedby the driver whenoperating the car.

In accordance with the present invention, I have provided means forindicating the thermal condition of the engine comprising anindicatingdevice or instrument proper locatedin a position convenientfor observation and connected in an operative manner with temperatureresponsive or sensitive element applied in suitable thermal relation tothe engine, preferably to the outside of an engine cylinder, when theelement is applied to a finned cylinder it is preferably applied to aportion of the exterior surfaces unprovided with coolingiins 3. Asillustrated, an indicating instrument 22 is mounted on the dash orinstrument board 16 and is connected by means of a flexible tube 21 tobulb 20 preferably of metal attached' to the cylinder, and preferablycontaining an expansible fluid, eitherv gas ory liquid. The bulb and itscontents thus lconstitute the temperature responsive part of thelapparatus. The specific construction of the indicating instrument properis no part of the present invention and this instrument may be of anysuitable character. As illustrated, it comprises a Bourdon tube 23 whichis in communication with the tube 21, the free'end of the Bourdon tubebeing connected-with a lever 24, pivoted at 25 and carrying on its outerend a toothed segment 26 which meshes with a pinion 27 carrying anindieatingl hand 28 which is adapted to move over a scale 29. Changes inpressure or volume due to the expansion and contraction of the fluid inthe bulb 20 will cause corre- -spending movements of the indicating handin a well understood manner.

As will be understood, the arrangement herein disclosed aims to disposethe temperavture responsive element or elements so as to secure thedesired influencing thereof, lin

accordance with the thermal condition of the' engine without having totap the cylinders` or when applied to the water cooled engine, withouthaving to tap the cooling system.

Therefore, I. apply a bulb or other temperature responsive element orcasing containing the same in intimate thermal Contact with a heatedpart of the engine, for instance to thel wall of a cylinder unprovided'with cooling fins, or to a part of the cooling system containing heatedcooling'fluid. I also preferably shape the bulb or other temperatureresponsive element so as to secure a large surface of contact,and'insulate the outer side of the hulb so as to retain heat, asillustrated. Bulb 20 is shown flattened out and appliedto the topportion of the cylinder, it a layer 30 of asbestos or otherl heat insuator, the bulb and asbestos layer being clamped in position by a metalcasing 31,"notched at 32 to permit passage of the tube 21 and attachedto the cylinder jacket in any suitable manner, as by means of threescrews 33,-'e'ngaging ears 34 formed in the casing, the casing and `earsbeing preferably formed of an integral sheet metal stamping, althoughother construction inay be employed. Preferably, and as shown, theinsulating layer 30 extends over an area substantially larger than thatof the bulb or othertemperatiire responsive instrument whereby radiationfrom the area of the cylinder wall surface in contact With the bulb isminimized and a more accurate measure of the cylinder temperature0btained. In order to improve the thermal contact between the flattenedbulb and the jacket wall, the bulb is preferably united to the wall'by ametallic film 35 formed by soldering, brazing, welding or by othermeans. While other heat conducting films may be employed, I. preferthose of metal.

Figure 6 illustrates my invention in connection with a motor of thewater cooled type. 'As shown, a temperature responsive element andcovering therefor, designated generally by 40, is attached to thecylinder jacket 41, the construction of the instrument 40 and its mannerof attachment to the jacket 41 being in all respects similar to what hasbeen disclosed in connection with Figures 1 to 3, inclusive.

From ythe foregoing it will be seen that I have provided a means forindicating the thermal condition of the engine which does notnecessitate the modification of or the interference with any part of theengine or its auxiliaries. It will be further seen that I have providedan effective and elicient means for indicating the thermal condition ofan air cooled engine and an improved means for insuring intimate thermalcontact between the temperature responsive element and the enginecylinder or jacket in the form preferably of a met-al film, this latterfeature being applicable to both air and Water cooled types of motors. i

While I have described my invention with reference to thetemperatureresponsive instrument of a fluid filled type, it will be understood thatother types, as for example,

those employing an electric current, may be used.

flattened side in intimate thermal conductivel contact with a portion ofthe louter surface of a cylinder wall of the motor, said meanscomprising a metallic casing extendin over the bulb and secured to themotor wal and ieu This application is a continuation` in part of mycopending application, Serial No.

a layer of non-conducting material between said casing and the bulb, anindicating instrument located in a position to be observed by the driverwhen operating the vehicle, and a means connectlng said instrument foroperating from bulb.

2. In temperature indicating .means for air cooled internal combustionmotors of motor vehicles, the combination of a temperature responsiveelement having an extended surface substantially conforming to andsecured in thermal contact on the outer surface of a cylinder walldefining a combustion s aceV of the motor, a casing contamng said eement and securin same to said wall, l5

said instrument, and indicating means oper- 20 ated by said element.

In testimony whereof I have aixed my signature to this specification;

HARRISON H. BOYCE.

